Fiber-optic sensors are increasingly being used as devices for sensing some quantity, typically temperature or mechanical strain, but sometimes also displacements, vibrations, pressure, acceleration, rotations, or concentrations of chemical species. The general principle of such devices is that light from a laser is sent through an optical fiber and there experiences subtle changes of its parameters either in the fiber or in one or several fiber Bragg gratings and then reaches a detector arrangement which measures these changes.
In particular a growing application field is the use of fiber optic sensing system for sensing when deployed in monitoring or production wells. Such sensors are particularly attractive because more conventional sensing systems are expensive to build, and in liquid environments susceptible to failure making them more expensive and difficult to maintain, Additionally, electrical systems are not well suited for in-well installation due to the hostile environment (pressures, temperatures, corrosion). Fiber optic systems do not suffer many of the limitations of electronics and are thus emerging as the technology of choice.
As the applications of fiber optic telemetry have expanded there is increased need to install multiple fiber optic sensors into the down-hole environment. Each sensor may require its own FIMT (fiber in metal tubing). The assembly of multiple sensors and the accompanying multiple FIMT's requires a number of optical fiber splice housings deployed throughout the down hole environment, In the current designs of these at high temperatures the housing can expand in length much greater than the fiber due to differences in the thermal expansion of metal and glass. This creates stress in the fiber that can affect the optical properties of the signal, or in worst case, cause the fiber to break.
There is a need to increase the reliability of the splice in these optical fiber splice housings and potentially eliminate the breakage of spliced optical fibers.